Hi Charles, On Jan 22, 2008 10:44 AM, Charles, Oliver <[EMAIL PROTECTED]> wrote: > We try to port openscenegraph to a device where only opengl es is > available. > Does anyone know if this was tried before? And if - if the sources are > available?
I don't know of any projects that have do so yet. > If not - does anyone have experience or any hints with porting opengl > applications to opengl es? > The problem in detail is that many of the opengl functions used by > openscenegraph are not available on opengl es , eg GL_POLYGON, Shading > or any functions introduced in OpenGl 2.0. Is there any well performing > algorithm to replace for example GL_POLYGON with eg GL_TRIANGLES (etc). The osgUtil::Optimizer and osgUtil::Tessellator will be able to help a bit. Items like shaders and other OpenGL state won't be able to map across to all versions of OpenGL ES, the same applies to display lists too. Most OpenGL state in the OSG is pretty loosely coupled virtue of the way that OpenGL state is wrapped up in subclasses from osg::StateAttribute. You could easily just not compile the problem state attributes, or perhaps have a non op implementation of these. The non op route might help with the job reading existing databases via the .ive and .osg plugins. Personally I'd tackle the task my tackling it in several passes - the first pass would be a very rough attempt, just commenting out or not compiling parts that don't compile. Also just use a stripped down osgUtil::SceneView or osgViewer::GraphicsWindowEmbedded based viewwer - see osgviewerGLUT and osgviewerSDL for examples of the later. Again taking an axe to bits that don't compile in osgViewer would get you past some of the difficult parts. Also set yourself a set of simple models that you'd like to load and see if you can get them working. Once this rough pass has been done one can reflect on what parts map easily, what parts don't and how the core OSG might be refactored to help a much cleaner support of OpenGL ES. Please feel free to bounce ideas off the OSG community. I'm sure I'm not the only one would love to see OpenGL ES supprt added in future version. BTW, what dev tools are you using right now? Robert. _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
